From the Guidelines
Citrate anticoagulation in CRRT is not contraindicated in most cases, including severe liver dysfunction or shock, as long as careful monitoring and management of potential complications are implemented. The Canadian Society of Nephrology commentary on the 2012 KDIGO clinical practice guideline for acute kidney injury suggests that regional citrate anticoagulation can be safely used in patients with severe liver failure, as citrate accumulation can be tracked by following the systemic ionized calcium level and the total calcium to ionized calcium ratio 1. In fact, adapted regional citrate anticoagulation has been safely performed in CRRT and extracorporeal liver assist devices in patients with severe liver failure 1.
Key Considerations
- Severe liver dysfunction or failure is not an absolute contraindication for citrate anticoagulation, as long as careful monitoring of citrate levels and calcium metabolism is performed 1.
- Shock is also not considered a contraindication for regional citrate anticoagulation, as several randomized controlled trials have safely used this approach in patients with severe septic shock 1.
- However, patients with severe hypocalcemia at baseline may be poor candidates for citrate anticoagulation due to the calcium-chelating effects of citrate.
- Citrate should be used cautiously in patients receiving massive blood transfusions, as blood products contain citrate preservatives that can contribute to accumulation.
Alternative Anticoagulation Strategies
- When citrate anticoagulation is not preferred, alternative anticoagulation strategies for CRRT include regional heparin, low-dose systemic heparin, or running the circuit without anticoagulation with increased circuit monitoring and possibly more frequent circuit changes.
- Monitoring for citrate toxicity includes regular assessment of ionized calcium, total calcium, acid-base status, and the total-to-ionized calcium ratio 1.
From the Research
Contraindications for Citrate Anticoagulation in CRRT
Citrate anticoagulation is a widely used strategy for continuous renal replacement therapy (CRRT), but there are certain situations where its use is contraindicated. The following are some of the conditions where citrate anticoagulation may not be recommended:
- Liver failure: Although some studies suggest that citrate anticoagulation can be safe in liver failure patients 2, 3, others have raised concerns about the risk of citrate toxicity in these patients 4, 5.
- High risk of citrate accumulation: Patients with liver dysfunction or other conditions that may lead to citrate accumulation should be closely monitored, and alternative anticoagulation strategies may be considered 4, 5.
- Severe metabolic derangements: Patients with severe acid-base disturbances or electrolyte imbalances may not be suitable candidates for citrate anticoagulation, as citrate can exacerbate these conditions 6.
Special Considerations
In certain situations, citrate anticoagulation may be used with caution, but close monitoring of the patient's condition is essential. These situations include:
- Acute liver failure: Citrate clearance may be decreased in patients with acute liver failure, and close monitoring of citrate levels and acid-base status is necessary 4.
- Acute-on-chronic liver failure: Patients with acute-on-chronic liver failure may be at higher risk of citrate toxicity, and alternative anticoagulation strategies should be considered 4.
- Patients with severe coagulopathy: Citrate anticoagulation may be beneficial in patients with severe coagulopathy, but close monitoring of bleeding risks and coagulation parameters is essential 3.